IndexAbstractIntroductionLiterature reviewCharacteristic sourcesPrinciples and classification of existing techniquesWastewater quality assessmentAbstractReal-time monitoring of wastewater quality remains an unsolved problem for the wastewater treatment industry . To comply with increasingly stringent environmental regulations, plant operators and industrial manufacturers have expressed the need for new standards and better comparability of existing techniques. A review of currently available methods for monitoring global organic parameters (BOD, COD, PH, DO etc.) is provided. The study examines both existing standard techniques and innovative new technologies with a focus on the potential of sensors for online and real-time monitoring and control. Current developments of virtual sensors for wastewater organic load monitoring are presented, and the interests and limitations of these techniques with respect to their application to wastewater monitoring are discussed. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essayKeywords: BOD; COD; DO;PH, wastewater, virtual sensor.IntroductionWater is nature's precious gift to human beings. The European Community decided in 1991 to oblige all EU member states to equip all cities whose organic wastewater load exceeds 15,000 population equivalents with wastewater treatment plants (to be implemented by 31 December 2000) and 2,000 equivalent inhabitants (to be implemented before 31 December 2005). The characterization of waste water entering and leaving treatment plants is an effective way to control the efficiency of the process and verify the final quality of the treated water. Typically, wastewater quality is characterized both by global parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD), total organic carbon (TOC) or total suspended solids (TSS), and by compounds of nitrogen and phosphorus. All values ​​must be lower than the maximum permitted values, depending on specific regulations. These provisions are of great importance but unfortunately of great importance but unfortunately the monitoring procedures currently carried out are not very satisfactory because they involve sampling, storage and laboratory analysis - a succession of sample handling, which considerably increases the risk of errors. There is now a growing need to limit sample manipulation and to develop rapid and accurate devices that allow a range of parameters to be monitored using direct field measurements. The aim of this study was to review both existing standard techniques and new innovative technologies with a focus on the potential of sensors for online and real-time monitoring and control. Literature Review The world is facing problems related to wastewater management. This is due to extensive industrialization, increasing population density, and highly urbanized societies (EPA, 1993; McCasland et al., 2008). Effluents generated by domestic and industrial activities constitute the main sources of the natural load of water pollution. This represents a large burden in terms of wastewater management and can consequently lead to a point source pollution problem, which not only considerably increases treatment costs but also introduces a wide range of chemical pollutants and microbial contaminants into water sources (EPA, 1993, 1996; Eikelboom and Draaijer, 1999; Preventionof pollution of water sources and the protection of public health, safeguarding water reserves against the spread of diseases, are the two fundamental reasons for wastewater treatment. This is achieved by removing substances that have high oxygen demand from the system through metabolic reactions of microorganisms, separation and sedimentation of solids to create an acceptable quality of wastewater effluent, and collection and recycling of microorganisms in the system or the removal of excess microorganisms from the system (Abraham et al., 1997). In municipal wastewater treatment systems, common water quality variables of concern are biological oxygen demand (BOD), chemical oxygen demand (COD), dissolved oxygen (DO), suspended solids, nitrates, nitrite and ammoniacal nitrogen, phosphate, salinity, and a number of other nutrients and trace metals (DeCico, 1979; Brooks, 1996). The presence of high concentrations of such pollutants above the critical values ​​established by national and international regulatory bodies is considered unacceptable in receiving water bodies. This is because, in addition to causing a serious inconvenience in wastewater treatment systems, they also lead to eutrophication and various health impacts on humans and animals (EPA, 2000; CDC, 2002; Runion, 2008). In recent years, the reuse of treated effluents that are normally discharged into the environment from municipal wastewater treatment plants is receiving increasing attention as a reliable water resource. In many countries, wastewater treatment for reuse is an important dimension of water resources planning and implementation. The goal is to release high-quality water resources for drinking use. Some countries, such as Jordan and Saudi Arabia, have adopted national policies to reuse all treated wastewater effluents and have therefore made considerable progress towards this goal. In China, the use of wastewater in agriculture developed rapidly several decades ago, and millions of hectares are irrigated with sewage effluent. . The general acceptance is that the use of wastewater in agriculture is justified by agronomic and economic reasons, although care must be taken to minimize negative impacts on health and the environment (FAO, 1992; Metcalf and Eddy, 2003 ; Rietveld et al., 2009; Sowers, 2009 ). [2004] studied industrial wastewater and groundwater, as well as the problem of groundwater pollution. V. Singh and CPS Chandel [2006] analyzed wastewater from Jaipur city, which is used for agricultural purposes. Furthermore, wastewater reuse is becoming increasingly important to supplement drinking water needs in some countries around the world. The option of wastewater reuse is becoming necessary and possible due to the increase in climate change, thus leading to drought and water scarcity, and the fact that regulations on the discharge of wastewater effluents have become more stringent leading to improved water quality (Rietveld et al., 2009). Characteristic sources Turbidity Erosion from mountain, riparian, stream bank and stream channel areas; Color Domestic and industrial waste, natural decay of organic materials 3. Odor Decaying wastewater, industrial waste. Temperature Domestic and industrial wastePH Domestic, commercial and industrial wasteChlorides Domestic waste, domestic water supply, groundwater seepageNitrogen Domestic and agricultural wastePrinciples and classification of existing techniquesIn addition to traditional laboratory analytical techniquesused in the water industry, recent years have seen the development of a range of innovative monitoring equipment. Although only a small number of such products have yet reached the market or been accepted, there is already a great diversity of techniques and technologies available, both commercially and in research laboratories, reported in the literature. As a result, several schemes have been used in an attempt to classify existing sensors and analyzers based on their respective properties. (Lynggaard-Jensen1999) listed eight different sensor/analyzer properties. Sensor Placement In situ, in-line, in-line; online, offline Sampling principle External sampling, no external sampling Filtration principle Filtration, no filtration Sample processing principle Continuous, batch Measuring principle Photometric, colorimetric, enzymatic, titrimetric, etc. 6. No. of Measurants Single Parameter, Multiple Parameter Need for Supplies Consumables, No Consumables Service Intervals Long, medium or short interval. Relevant sensor properties (according to Lynggaard-Jensen A 1999) that should be taken into account before their introduction into wastewater systems (e.g. for process monitoring or control). Indeed, key features such as cost of ownership, ease of use, sensor placement, as well as response time, will influence consumer choice. Other technical aspects such as measurement principle, reliability, precision and detection limits will also determine whether or not the technology will be accepted and promoted as a standard (or alternative) method by the end user and relevant authorities. It is evident, therefore, that both the performance characteristics (range, linearity, response time, accuracy, detection limit, etc.) and the intrinsic properties of the sensors (single or multiparametric, need for external sampling and filtering, intrusion/non-intrusive) are of great importance when examining existing and new methodologies for wastewater systems. Wastewater quality assessment To assess the wastewater pollution status of water bodies, the following water quality parameters were analyzed. Keep in mind: This is just a sample. Get a customized document from our expert writers now. Get a Custom EssayTurbidity; Wastewater is normally cloudy, similar to dirty dishwater or toilet wastewater containing other floating materials such as feces, pieces of paper, cigarette butts, matches, grease, plant debris, fruit peels, soaps, etc. Turbidity increases as the wastewater becomes stronger. The degree of turbidity can be measured and tested using turbidication rods or turbidimeters, as is done for testing raw water supplies.Color; The color of the wastewater can normally be detected with the naked eye and indicates the freshness of the wastewater. If its color is yellowish, gray or light brown, it indicates fresh sewage. However, if the color is black or dark brown, it indicates stale sewage and septic. Other color can also form due to the presence of some specific industrial waste. Odor; Fresh wastewater is virtually odorless. However, within 3 to 4 hours, it becomes stale and all the oxygen in the wastewater is basically used up. It then begins to emit unpleasant odors, particularly that of hydrogen sulfide gas, which is formed due to the decomposition of wastewater. The odor of water or wastewater can be measured with a term called the odor threshold number (TON), which represents the amount of dilution required to make the sample odor-free..